It's always nice to learn about people's experience in Japan, so I appreciate seeing your two cents on the matter.
As for me, my desire to live in Japan comes from the culture itself. I want to see how it is like to live with an entirely different group of people (as well as how life is like to live by myself). I also just got back to learning Japanese (日本語), which is a huge motivation for me to live in Japan. There is a lot about Japan that I am interested in and not just manga, video games, or anime (otherwise I wouldn't have considered moving). I also intend on becoming an ESL teacher for a career, teaching in various countries in East, Southeast, and South Asia.
I have a lot of friends who went to Japan or Korea with a very similar mindset. "Enjoy the culture, language, and swag; teach English to eek out a living and get placed more easily in a foreign country." It's not a bad plan. It's a well-worn path, I think.
Just know that it will not satisfy you. It will be pretty cool, though. I like the food better over there in general, but then again, I couldn't read any ingredient lables, either... Hard to say it is much healthier definitively, but I will say that I lost about 10lbs in the month I lived in Japan. I also walked a lot and took the train, at times.
Korea is probably a better fit for a westerner, ultimately. Korea doesn't interest everyone, though. Japan is nice for buying stuff, food, scenery... Entertainment. Lust of the eyes. But trying to have deep relationships with other people there is very difficult. The language barrier is bad enough, but you also have culture working against you as well. Many Japanese see foreigners as scary, just like most people are initially wary of people who look, act, and talk differently. Even though I was the second best at Japanese in my group, after a month I was extremely tired of no one speaking English. It wore me out mentally. It was hard for people to relate to me, and me to them. I got severely homesick. Almost had a mental breakdown by the time I got to the flight home.
It's not for everyone. I'd suggest an extended visit to Japan before setting up an entire life and career over there!
As a last aside, going to Japan really made me lose my appetite for anime and manga. I can still enjoy a good one at times, but once you go there and you see entire stores overflowing with the stuff, you begin to realize that the stuff isn't as special as you may have once believed. Most of it bad quality, and all of it is just endless rehash. When you do find a good one, though, I admit, it is nice. The Japanese really do have a talent for an effective brand of visual storytelling.
So how'd you survive not knowing Japanese?
I do know a decent amount of Japanese, actually. I mostly know syntax and grammar, as I have a limited vocabulary. But since I was taught Japanese in the same way that a person learns their first language from their parents, it's easy for me to learn new words. Mr. Suzuki, my Japanese teacher, was a very pragmatic person. Very effective teaching methods. It helped that I was highly motivated to learn, however. The slackers in the class decided they didn't want to work, and so they did poorly.
I admit, I am very rusty. Once you leave the environment where the language is used, you forget things. It can come back to you, but if you don't use it, you can lose it to an extent.
Interestingly, after a month of being in Japan, once I got back home I would mix up my Rs and Ls a bit in my English speaking. It also became mentally excruciating to spell things verbally, or to comprehend other people doing the same thing, e.g., "bee ee en ee ay tee etch, beneath." It has to do with how my brain learned Japanese. It was interesting.
vs. 
